PHOTOTYPE PLATE NO. XXI L 35 



exhibiting a pinnate plan of disposition, subtend from every side of their central axis, more 

 nearly approaching, in this respect, a verticillate form of growth. 



In respect to their obvious pinnate character, the tentacles of this species more nearly 

 resemble those of a Phymanthus, of which genus a typical variety is included in Plate III. 

 of the coloured series. This fact has been recognised by Prof A. C. Haddon, to whom the 

 photographs were submitted, and who, in the first instance, was inclined to identify it with a 

 species, also obtained by him from Torres Strait, upon which he has proposed to confer the 

 title of Pliymantlins untscosus. The relatively few tentacles, twenty-four only, possessed by 

 this type preclude, however, its admission among the typical Phymanthi, and a further con- 

 sultation of the older works of Zoophytology has determined the author upon relegating it, 

 provisionally, to the genus Megalactis of Ehrenberg. As a hitherto undescribed species of 

 that genus, it is associated in this volume with the title of Megalactis GriffitJisi ; the specific 

 name adopted being conferred by way of compliment to Sir Samuel Griffiths, the eminent 

 Queensland statesman, to whom this work is dedicated. 



The habits of this new Megalactis differ in a marked manner from those of the preceding 

 species. Instead of inhabiting sandy flats or tidal pools, in the full glare of the sun, it prefers the 

 shelter of some rocky or coral boulder. Its column does not penetrate deeply beneath the sur- 

 face, and it can be detached with comparative ease from its chosen fulcrum. The tentacles are 

 usually a clear brown or French grey, with a distinct pale greenish stripe running up their centre. 

 The central disk is distinctly marked with radiating lines that correspond with the subjacent mesen- 

 terial divisions, which, as clearly shown in the accompanying photographic reproduction, present 

 distinct features that accord with their corresponding mesenterial cycles. Thus, those that over- 

 lie the primary developmental cycle are plainly indicated by the six longest and thickest white lines 

 that radiate from the stomadeeum or oral aperture ; those representing the second developmental 

 cycle are as clearly defined by the six shorter white lines, intervening between the six primary 

 ones, that do not reach the margin of the mouth. The two nearer of those secondary radial lines 

 are somewhat obscured by the tentacular ramifications. The lines corresponding with the sub-divi- 

 sion possessed by the three combined mesenteric cycles are represented by the twenty-four finer 

 and more variegated lines that extend from between the outer ends of the preceding twelve lines to 

 the extreme edge of the periphery. In consequence of the thickly intervening tentacular sub-divi- 

 sions, only some half-dozen elements of this peripheral linear series are conspicuous in the 

 photographic reproduction. It is, finally, worthy of note, that the lip of the siphonoglyphe or 

 gonidial groove is clearly represented by a narrower indentation at the upper angle of the mouth 

 or stomad^um. The fine specimen that furnished the subject of this illustration was photo- 

 graphed on the Warrior reef, in Torres Strait. 



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